WO 2016027283, New patent, Indacaterol, Reddy-Cheminor Inc

Beta 2 adrenoceptor agonist

Chronic obstructive pulmonary disease

WO 2016027283, New patent, Indacaterol, Reddy-Cheminor Inc

A process for preparing indacaterol and salts thereof

REDDY, G Pratap; (IN).
SUNKU, Venkataiah; (IN).
BABU, Sunkaraneni Suresh; (IN)

The present invention relates to a process for preparing indacaterol or salts thereof. The process comprises of forming compound of Formula 1 by reacting compound of Formula 2 and compound of Formula 3 in the presence of a solvent to Form compound of Formula 4, 5 which on removal of the protecting groups forms compound of Formula 1.

Indacaterol maleate is a beta-selective adrenoceptor agonist with potent bronchodilator activity. Indacaterol is chemically known as 5-[(R)-2-(5, 6-diethyl-indan-2- yl amino)-l-hydroxy-ethyl ]-8-hydroxy-(lH)-quinolin-2-one.

US7534890 claims a process to prepare 5-[(R)-2-(5,6-diethyl-indan-2-ylamino)- 1 -hydroxy-ethyl] -8-hydroxy-(l H)-quinolin-2-one salt. One of the key steps in the process is reacting an epoxide, such as 8-substituted oxy-5-(R)- oxiranyl-(lH)-quinoline-2-one [Formula (I)] with an amine, such as 2-amino-(5,6-diethyl)-indan to form an intermediate 5-[(R)-2-(5,6-diethyl-indan-2-ylamino)-l -hydroxy-ethyl]-8- substituted oxy-(lH)-quinolin-2-one [Formula (Ha)].

The drawback of this process is opening of epoxide ring is not regioselective and thereby resulting, in formation of substantial quantities of impurities as by products, Formula (lib) and Formula (lie) resulting in overall lower yields. The quantity of 2- amino-(5,6-diethyl)-indan used in this step is also large excess than theoretical amounts. Subsequent improvements also did not address this problem effectively.

WO 2013/132514 discloses a process to prepare Indacaterol involving the steps of treating a compound of Formula (III), wherein L is a leaving group, with the amine, 2-amino-(5,6-diethyl)-indan or its acid addition salts to obtain a compound of Formula (IV) or its acid addition salts.

Though higher yields have been claimed, the process has not overcome completely all the problems mentioned earlier.

There is a need for developing a more efficient process for preparing Indacaterol or salts thereof especially for large scale production with higher yields.

 

The reaction scheme of synthesis of compound of Formula 3 is represented below.

Formula 3 Formula 13 Formula 12

xample 1

Process to prepare 5-[ (R)-2-(5, 6-diethyl-indan-2-ylamino)-l-hydroxy-ethyl]-8-hydroxy-( lH)-quinolin-2-one

2-Chloro-5,6-diethylindan (4.2g) was added to a solution of 5-[(R)-(2-amino-l-hydroxy-ethyl)-8-phenylmethoxy-(lH)-quinolin-2-one (6g) in dimethylformamide (20ml) followed by addition of N,N-diisopropyl-N-ethylamine (3.6 g) and sodium iodide (lg) at room temperature and stirred for 10 minutes. The reaction mixture was heated to 90° C and the temperature was maintained at 90 °C till the completion of reaction. The reaction mass was cooled to room temperature and diluted with dichloromethane (100ml) and water (100 ml) and stirred for 30 minutes. The organic phase was separated and the aqueous layer was extracted with dichloromethane. Combined organic layer was washed with water, dried and concentrated. The resulting residue was dissolved in isopropyl alcohol under reflux and cooled slowly to obtain 5-[(R)-2-(5,6-diethyl-indan-2-ylamino)-l-hydroxy-ethyl]-8-phenylmethoxy -(lH)-quinolin-2-one, which was isolated by filtration and dried under vacuum (7.4 g). Yield: 79.3 %. Purity of the product is >95 % (HPLC).

Example 2

Process to prepare 5-[(R)-2-(5, 6-diethyl-indan-2-ylamino)-l-hydroxy-ethyl]-8-hydroxy-( lH)-quinolin-2-one

Solution of 5-[(R)-2-(5,6-diethyl-indan-2-ylamino)-l-hydroxy-ethyl]-8-phenylmethoxy-(lH)-quinolin-2-one (lOg) in methanol (100ml) and acetic acid (20ml) was hydrogenated using palladium on charcoal 5% (1.5g) until completion of the reaction. The mixture was filtered over celite and the filtrate was concentrated at 55°C under vacuum. The residue obtained was dissolved in hot methanol to precipitate 5-[(R)-2-(5,6-diethyl-indan-2-ylamino)-! -hydroxy-ethyl]-8-hydroxy-(lH)-quinolin-2-one.

Example 3

Process to prepare 5-[(R)-2-(5, 6-diethyl-indan-2-ylamino)-l-hydroxy-ethyl]-8-hydroxy-(lH)-quinolin-2-one maleate

Crude 5-[(R)-2-(5,6-diethyl-indan-2-ylamino)-l -hydroxy-ethyl]-8-hydroxy-(lH)-quinolin-2-one prepared by the process of Example 2 was added to a solution of maleic acid (2.6g) in methanol and the resulting clear solution was slowly cooled to 5° C and stirred for 2 hours at the same temperature. The slurry was filtered, washed with cold methanol and dried to obtain 5-[(R)-2-(5, 6-diethyl-indan-2-ylamino)-l-hydroxy-ethyl]-8-hydroxy-(lH)-quinolin-2-one maleate (8.8g). Yield: 83.5 %. Purity of the product is >99%. E.e. >99 %.

Example 4

Process for preparing 5-[(R)-(2-phthalimido-l-hydroxy-ethyl)-8-phenylmethoxy-(lH)-quinolin-2-one

Diisopropylethylamine (6g) was added to a solution of phthalimide (6g) in dimethylformamide (30 ml) at room temperature. To this solution, 8-(phenylmethoxy)-5-[(R)-2-bromo-l-hydroxy-ethyl]-(lH)-quinoline-2-one (11 gm) was added slowly followed by sodium iodide (1 g). The resulting mass was heated to 90°C and stirred till the completion of reaction as monitored by TLC. The reaction mass was diluted with water (200 ml) and the crude product was isolated by filtration. The wet filter cake was suspended in water (60 ml), stirred for 1 hour, filtered, washed with water to obtain 5-[(R)-(2-phthalimido-l-hydroxy-ethyl)-8-phenylmethoxy-(lH)-quinolin-2-one (10.4 gm) after drying. Yield: 80.7 %.

Method A- Process for preparing 5-[(R)-(2-amino-l-hydroxy-ethyl)-8-phenylmethoxy-(lH)-quinolin-2-one

To a solution of 5-[(R)-(2-phthalimido-l-hydroxy-ethyl)-8-phenylmethoxy-(lH)-quinolin-2-one ( 13.2 g) in a mixture of isopropanol (86 ml) and water (14 ml) sodium borohydride (4.6 g) was added slowly at room temperature and stirred overnight. Thereafter, the pH of the reaction mass was lowered to 5.5 with acetic acid, and then the reaction mass was heated to reflux for two hours. Isopropanol was distilled out under reduced pressure. The residue was diluted with ethyl acetate (120 ml) and concentrated hydrochloric acid (8 ml) was added and stirred for 15 minutes for the salts to precipitate out. The reaction mass was filtered and the salt was washed with ethyl acetate. To the clear filtrate concentrated hydrochloric acid (10 ml) was added and stirred at 5° C for 30 minutes for 5-[(R)-(2-amino-l-hydroxy-ethyl)-8-phenylmethoxy-(lH)-quinolin-2-one to separate out as hydrochloride salt. The product was isolated by filtration and dried under vacuum (8.2 g). The hydrochloride salt was dissolved in minimum amount of water and basified with sodium hydroxide solution. The product was isolated as free amine by concentrating the solution under reduced pressure and extracting the residue with isopropyl alcohol and distilling out the solvent (7.45 g). Yield 80 %.

1H-NMR (CDC13) ppm: 2.56-2.70 (m, 2H), 3.35 (s, br, 2H, exchangeable), 4.89 (m, 1H), 5.29 (s, 2H), 5.76 (s, 1H, exchangeable), 6.53 (d, 1H), 7.11-7.19 (dd, 2H), 7.29-7.36 (dd, 1H), 7.39 (d, 2H), 7.57 (d, 2H), 8.21 (d, 1H), 10.7 (s, br, 1H, exchangeable).

Method B- Process for preparing 5-[(R)-(2-amino-l-hydroxy-ethyl)-8-phenylmethoxy-( lH)-quinolin-2-one

To a solution of 5-[(R)-(2-phthalimido-l-hydroxy-ethyl)-8-phenylmethoxy-(lH)-quinolin-2-one ( 10 g) in ethanol (60 ml) hydrazine hydrate (4.8 g) was added and refluxed the mixture for about 6 hours. The solvent was distilled out under reduced pressure. To the residue, concentrated hydrochloric acid (16 ml) was added and heated to about 80°C and maintained till the completion of the reaction. The reaction mass was cooled to room temperature and filtered. The clear filtrate was basified and concentrated under reduced pressure. The product was isolated as free amine (5.8 g) by extracting with isopropyl alcohol and distilling out the solvent. Yield: 83%.

Method C

Preparation of 5-(2-benzylamino-l-hydroxy-ethyl)-8-phenylmethoxy-( lH)-quinolin-2-one 5-Acetyl-8-phenylmethoxy-(lH)-quinolin-2-one (30 g) was refluxed with selenium dioxide

(11.5 g) in a mixture of dioxane (350 ml) and water (30 ml) for 16 hours. The reaction mixture was diluted with dioxane (150 ml) and precipitated inorganic salts were removed by filtration. Clear filtrate was concentrated to about 60 ml under vacuum and diluted with methanol (100 ml). The reaction mass was cooled to 15° C and benzylamine (7.5 g) was added slowly over a period of 45 minutes and stirred at the same temperature for two hours.

The reaction mass was further cooled to 0°C and sodium borohydride (2.8 g) was added slowly over a period of one hour. Thereafter, the reaction mass was stirred at room temperature for 12 hours. The reaction mixture was concentrated under vacuum and diluted with 300 ml water and stirred at 20° C for three hours. The precipitated product was collected by filtration, washed with water followed by isopropyl ether and then dried (28.2 g) to obtain 5-(2-benzylamino-l-hydroxy-ethyl)-8-phenylmethoxy-(lH)-quinolin-2-one.

Example 5

Preparation of 5-acetyl-8-phenylmethoxy-(lH)-quinolin-2-one

To a solution of 5-acetyl-8-hydroxy-(lH)-quinolin-2-one (35 g) in dimethylformamide (175 ml) potassium carbonate (35 g) was added at room temperature and stirred for 10 minutes. To the suspension, benzylbromide (32 g) was slowly added over a period of 30 minutes and stirred for 2 hours at the same temperature for completion of reaction (monitored by TLC). The reaction mass was diluted with water (800 ml) and stirred for 20 minutes for the product to precipitate out. The product was filtered, washed with water and dried under vacuum to get the title product (48 g).

Example 6

Preparation of 5-(2-bromoacetyl)-8-phenylmethoxy-( lH)-quinolin-2-one

Boron trifluoride-diethyletherate (29 ml) was slowly added to a solution of 5-acetyl-8-phenylmethoxy-(lH)-quinolin-2-one (50 g) in dichloromethane (500 ml) at 0° C and stirred for 10 minutes at the same temperature to get a thick precipitate. The reaction mass was heated to reflux temperature and bromine solution was added (29 g in 190 ml dichloromethane) slowly over a period of 2 hours under reflux (the HBr fumes coming from the condenser was scrubbed). Thereafter, the reaction mass was refluxed for further 45 minutes. The solvent was distilled out completely under vacuum and the mass was triturated with 10% aqueous sodium carbonate solution (100 ml). The suspension was filtered, washed with water and the crude product was taken for the next stage reaction.

Example 7

Preparation of 5-(2-phthalimido-l-oxo-ethyl)-8-phenylmethoxy-(lH)-quinolin-2-one

Potassium carbonate (33.4 g) was added to a solution of phthalimide (21.73 g) in dimethylformamide (80 ml) at room temperature and stirred for 10 minutes. To this suspension, crude 5-(2-bromoacetyl)-8-phenylmethoxy-(lH)-quinolin-2-one of example 6, dissolved in dimethylformamide (120 ml), was added slowly over a period of 20 minutes. The resulting suspension was stirred at 50° C for about 1 hour for the completion of reaction as monitored by TLC. The mixture was diluted with water (800 ml) and the crude product was isolated by filtration. The wet filter cake was suspended in water (600 ml), stirred for 1 hour, filtered, washed with water and dried under vacuum to get 5-(2- phthalimido-l-oxo-ethyl)-8-phenylmethoxy-(lH)-quinolin-2-one (67.4 g). Over all yield

(after two steps): 90%.

Example 8

Preparation of 5-[(R)-(2-phthalimido-l-hydroxy-ethyl)-8-phenylmethoxy-(lH)-q inolin-2-one

To a solution of (R)-2-methyl-CBS-oxazaborolidine (1M in toluene, 4.2 ml) in dry

tetrahydrofuran (THF, 50 ml) Borane-diethylaniline (19 ml) was added slowly at - 10° C

and the contents were stirred at the same temperature for 15 minutes. A solution of 5-(2-

Phthalimido-l-oxo-ethyl)-8-phenylmethoxy-(lH)-quinolin-2-one ( 8.3 g), of example 7, in

a mixture of dry THF (50 ml) and dichloromethane (50 ml), was added slowly to the

reaction mass at - 10° C. The reaction mass was further stirred for 2 hours and then

methanol was added and the temperature was slowly raised to room temperature. Dilute

sulfuric acid (6N, 10 ml) was added to the reaction mixture and stirred for 15 minutes. The

reaction mixture was concentrated under vacuum and the crude mass was extracted with

ethyl acetate. The organic phase was washed with dilute sulfuric acid and then water. The

solvent was distilled out completely under vacuum and triturated with hexane. The

compound was isolated by filtration and dried (7.6 g). Yield: 91.1%. e.e.. >97%.

Example 9

Process of preparing 2-chloroindan

2-hydroxy indan (lOOg) was dissolved in 1, 2-dichloroethane (400 ml) and added to thionyl

chloride (125 g) slowly over a period of an hour. Temperature was maintained at less than

10° C. Thereafter, the reaction mass was slowly heated and refluxed till the completion of the reaction. The reaction was monitored by TLC. The reaction mass was cooled to room temperature and poured in to ice water, stirred for 1 hour and organic layer was separated. The aqueous layer was extracted with dichloroethane. Organic layers were combined and washed with water, sodium bicarbonate solution and dried over anhydrous sodium sulphate. Solvent was distilled out completely and the crude product was distilled under vacuum to obtain 2-chloroindan as a colorless liquid (118 g).

Example 10

Process for preparing 5-acetyl-2-chloroindan

Aluminium chloride (146 g) was added in small lots to nitromethane (500 ml) and the solution was cooled to 5° C under inert atmosphere while stirring. Acetyl chloride (84 g) was slowly added keeping the temperature at 5° C. Solution of 2-chloroindan (118 g) was slowly added in acetyl chloride (84 g) keeping temperature at 5° C. After completion of reaction, monitored by TLC, the reaction mass was poured into cold IN HC1 (2000 ml) solution and stirred for 30 minutes. The product was extracted into di-isopropyl ether. The combined organic layer was washed with water, bicarbonate solution, brine and dried over anhydrous sodium sulphate. The solvent was completely distilled out to obtain 5-acetyl-2-chloroindan as yellow waxy solid (130 g).

Example 11

Process for preparing 2-chloro-5-ethylindan

1 Liter hydrogenation vessel was charged with 50 grams of 5-acetyl-2-chloroindan, 400 ml of methanol and 10 ml of acetic acid. Palladium on charcoal 5% (5 g) was added and the reaction mass was hydrogenated until complete conversion to 2-chloro-5-ethylindan. The mixture was filtered over a bed of celite. The filtrate was concentrated under reduced pressure to obtain 2-chloro-5-ethylindan as an oily mass (42 g).

Example 12

Process for preparing 5-acetyl-2-chloro-6-ethylindan

5-acetyl-2-chloro-6-ethylindan was prepared from 2-chloro-5-ethylindan (20 g) in accordance with the procedure followed in Example 10.

Example 13

Process for preparing 2-chloro-5, 6-diethylindan

Hydrogenation of 5-acetyl-2-chloro-6-ethylindan using Palladium on charcoal adopting the procedure as reported in Example 11, gave 2-chloro-5, 6-diethylindan as a liquid. The crude product was distilled under vacuum to get colorless liquid.

1H-NMR (CDC13) ppm: 1.19-1.29 (t, 6H), 2.61-2.66 (q, 4H), 3.13-3.18 (dd, 2H), 3.36-3.41 (dd, 2H), 4.66-4.72 (m, 1H), 7.05 (s, 2H).

////////////WO 2016027283, New patent, Indacaterol, Reddy-Cheminor Inc

WO 2016027077, Cipla Ltd, New patent, Dabigatran

(WO2016027077) PROCESSES FOR THE PREPARATION OF DABIGATRAN ETEXILATE AND INTERMEDIATES THEREOF

WO 2016027077, Cipla Ltd, New patent, Dabigatran

CIPLA LIMITED [IN/IN]; Cipla House Peninsula Business Park Ganpatrao Kadam Marg Lower Parel Mumbai 400 013 (IN).

RAO, Dharmaraj Ramachandra; (IN).
MALHOTRA, Geena; (IN).
PULLELA, Venkata Srinivas; (IN).
ACHARYA, Vinod Parameshwaran; (IN).
SINARE, Sudam Nanabhau; (IN)

Dabigatran etexilate (a compound of Formula I) is the international commonly accepted nonproprietary name for ethyl 3-{[(2-{[(4-{(hexyloxy)carbonyl]carbamimidoyl}phenyl)amino]methyl}-1 -methyl-1 H- benzimidazol-5-yl)carbonyl](pyridin-2-yl)amino}propanoate,

 

(I)

Dabigatran etexilate is the pro-drug of the active substance, dabigatran. The mesylate salt (1 : 1 ) of dabigatran etexilate is known to be therapeutically useful as an oral anticoagulant from the class of the direct thrombin inhibitors and is commercially marketed as oral hard capsules as Pradaxa™ in Australia, Europe and in the United States; as Pradax™ in Canada and as Prazaxa™ in Japan. Additionally, it is also marketed in Europe under the same trade mark for the primary prevention of venous thromboembolic events in adult patients who have undergone elective total hip replacement surgery or total knee replacement surgery.

Dabigatran etexilate was first described in U.S. Patent No. 6,087,380, according to which the synthesis of dabigatran etexilate was carried out in three synthetic steps as depicted in Scheme 1.

Scheme 1

 

1. HCL , EtOH

2. (NH4)2C03, EtOH

 

Dabigatran etexilate

II. HCI

The process involves the condensation between ethyl 3-{[3-amino-4-(methylamino)benzoyl] (pyridin-2-yl)amino}propanoate (compound VI) and N-(4-cyanophenyl)glycine (compound VIII) in the presence of Ν,Ν'-carbonyldiimidazole (CDI) in tetrahydrofuran (THF) to give the hydrochloride salt of ethyl 3-{[(2-{[(4-cyanophenyl)amino]methyl}-1-methyl-1 H-benzimidazol-5-yl)carbonyl](pyridin-2-yl)amino} propanoate (compound IV), which is subsequently reacted with ethanolic hydrochloric acid, ethanol and ammonium carbonate to give the hydrochloride salt of ethyl 3-{[(2-[{(4-carbamimidoylphenyl)amino]methyl}-1-methyl-1 H-benzimidazol-5-yl)carbonyl](pyridin-2-yl)amino} propanoate (compound II). Finally, the reaction between compound II and n-hexyl chloroformate (compound IX), in the presence of potassium carbonate, in a mixture of THF and water, affords dabigatran etexilate of Formula (I) after work- up and chromatographic purification. However, no information is given about the purity of the isolated dabigatran etexilate (I) product. Further, the process is not viable industrially as it requires chromatographic purification in several of its steps, thus making it very difficult and costly to implement on an industrial scale.

In order to simplify the process for obtaining dabigatran etexilate described in U.S. Patent No. 6,087,380, several alternative processes have been developed and reported in the art.

EP2118090B discloses a process for the preparation of the intermediate compound of Formula (II) by crystallization from a salt with p-toluenesulfonic acid. The amidine salt (ll-pTsOH) is obtained from a compound of formula (IV), which is also isolated in the form of a hydrobromide salt, (IV-HBr).

EP2262771A discloses a process for the preparation of the intermediate compound of Formula (IV), which is obtained in the form of a salt with oxalic acid. This document indicates that the oxalate intermediate of the compound (IV) crystallizes easily and is a good synthesis intermediate to obtain the amidine hydrochloride salt (ll-HCI) with high purity on an industrial scale. The compound (IV) in oxalate salt form is transformed in dabigatran following the process disclosed in WO 98/37075.

WO 2006/000353 describes an alternative process for the synthesis of dabigatran etexilate as depicted in Scheme 2.

 

Dabigatran etexilate

The process involves condensation between ethyl 3-{[3-amino-4-(methylamino)benzoyl](pyridin-2-yl)amino}propanoate (compound VI) and 2-[4-(1 ,2,4-oxadiazol-5-on-3-yl)phenylamino]acetic acid (compound Villa) in the presence of a coupling agent such as CDI, propanephosphonic anhydride (PPA), or pivaloyl chloride, to give ethyl 3-{[(2-{[(4-{1 ,2,4-oxadiazol-5-on-3-yl}phenyl)amino]methyl}-1 -methyl-1 H-benzimidazol-5-yl)carbonyl](pyridin-2-yl)amino}propanoate (compound IVa), which is subsequently hydrogenated in the presence of a palladium catalyst to give ethyl 3-{[(2-{[(4-carbamimidoylphenyl)amino]methyl}-1-methyl-1 H-benzimidazol-5-yl)carbonyl](pyridin-2-yl)amino} propanoate (compound II). The compound II is acylated with n-hexyl chloroformate (compound I) to give dabigatran etexilate. Finally, dabigatran etexilate is converted into its mesylate salt. Although the patent describes the HPLC purities of intermediate compounds II, IVa, Villa and VI, no information is given concerning the purity of the isolated dabigatran etexilate or the mesylate salt thereof.

WO 2010/045900 discloses a process to prepare the intermediate amidine hydrochloride compound (ll-HCI) from the oxalate salt of the compound (IV) by reacting with hydrogen chloride in ethanol, followed by reaction with ammonium carbonate to avoid chromatography which is not feasible on an industrial scale.

WO 2014/012880 discloses a process to prepare an intermediate of dabigatran etexilate (compound IV) by reacting carboxylic acid (compound VIII) with diamaine (compound VI) in the presence of the coupling agent CDI, followed by reaction with 6 equivalents of acetic acid at 130°C to obtain compound IV in acetate salt form, having a purity of 94%. The isolated solid is further recrystallized from ethanol to obtain a purity of 99%. The purified (compound IV. acetate) is reacted with hydrogen chloride in the presence of an alcohol, and then with ammonia in an aqueous medium to form the amidine hydrochloride salt (compound ll-HCI) in the presence of water.

The synthesis of intermediate compound II has been reported in the patent literature and known methods require either chromatographic purification or a lengthy purification procedure, such as converting the compound into the HCI salt followed by recrystallization, to obtain 97% pure intermediate compound II. In previously reported methods, the product yield is undesirably less than 50 %.

Similarly, the intermediate compound IV prepared by CDI mediated coupling with glycine derivatives followed by acetic acid mediated cyclization according to known methods results in the formation of highly impure products, which require purification by either column chromatography or by converting the crude reaction mixture to suitable salts. Previously reported methods afford low product yields and purity, which mean that such processes are not suitable for the commercial scale production of dabigatran.

In view of the foregoing, it is of great interest to continue investigating and develop other alternative simplified processes for the large scale industrial production of the active pharmaceutical ingredient dabigatran etexilate or salts thereof, which avoid complicated and costly purification steps in the synthesis of intermediates, while maintaining a high quality of synthesis intermediates and improving the yields of each step of reaction.

SCHEME 3

SCHEME4

Examples:

Example 1. Preparation of DAB Glycin-CDI complex of Formula (VII)

71.02 g (0.438 mol) of CDI was dissolved in 700 ml dichloromethane under nitrogen atmosphere. Added 66.89 g (0.379 mol) of 2-(4-cyanophenylamino)acetic acid of Formula (VIII), under stirring at 20-25°C and stirred for 90-100 minutes. Solid was isolated by filtration under nitrogen atmosphere and washed with 100 ml dichloromethane to yield DAB Glycin-CDI complex.

Example 2. Preparation of ethyl 3-(2-((4-cyanophenylamino)methyl)- l-methyl-N- (pyridin-2-yl)-IH-benzo[d]- imidazole-5-carboxamido) propanoate of Formula (IV)

DAB Glycin-CDI Complex obtained in Example 1 was stirred in 650 ml toluene. Added 100 g (0.292 mol) of ethyl 3-(3-amino-4-(methyl amino)-N-(pyridin-2-yl)benzamido)propanoate of Formula (VI) to the reaction mass and stirred for 3 hours at -45-50°C. The reaction mass was further refluxed for 3 hours. The reaction mass was cooled to 75-80°C, added 50 ml ethanol, further cooled to 20-25°C and stirred for 6 hours. The solid was isolated by filtration and washed with 100 ml toluene.

The wet cake was stirred in 500 ml water at 20-25°C for about 1 hour. The solid was isolated by filtration, washed with 100 ml water and dried in vacuum below 60 °C.

Yield: 120 g

Efficiency: 85%

Example 3. Preparation of ethyl 3-(2-((4-carbamimidoylphenylamino)methyl)-l-methyl-N-(pyridin-2-yl)-IH-benzo[d]imidazole-5-carboxamido) propanoate of Formula (II)

100 g (0.207 mol) of ethyl 3-(2-((4-cyanophenylamino)methyl)- l-methyl-N- (pyridin-2-yl)-IH-benzo[d]- imidazole-5-carboxamido) propanoate of Formula (IV) was added to 1000 ml EtOH.HCI (32-35%w/w) at 5-10°C under nitrogen atmosphere and stirred for 24 hours at 15-20°C. The solvent was distilled off in vacuum below 40°C. Added 500 ml ethanol and cooled to 0-5°C. The pH of the reaction mass was adjusted to 9.5-10.0 by addition of 400 ml EtOH.NH₃ (10-13%w/w). The temperature of the reaction mass was raised to 20-25°C and stirred for 12 hours. The reaction mass was filtered and the clear filtrate was partially distilled to the half volume below 40°C. The temperature of the reaction mass was raised to 55-60°C. Added 600 ml ethyl acetate at reflux. The reaction mass was cooled to 20-25°C and stirred further for 5 hours. The solid was isolated by filtration and washed with 100 ml-ethyl acetate. The solid was dried in vacuum below 45 °C.

Yield: 72.5 g

Efficiency: 70%

Example 4. Preparation of DAB etexilate of Formula (I)

120 ml acetone, 60 ml water, 16.6 g (0.120 mol) potassium carbonate and 20g (0.040 mol) of ethyl 3-(2-((4-carbamimidoylphenylamino)methyl)-l-methyl-N-(pyridin-2-yl)-IH-benzo[d]imidazole-5-carboxamido) propanoate of Formula (II) were stirred at 20-25°C. A solution of 9.88 g (0.060 mol) of hexyl chloroformate of Formula (IX) in 50 ml acetone was added to the reaction mass at 15-20°C in 1 .5 hours. The reaction mass was further stirred for 2 hours at 15-20°C. The precipitated solid was filtered and washed with 40 ml water.

The wet cake was dissolved in 160 ml acetone at 20-25°C. The insoluble were removed by filtration. Added 160 ml water to the clear filtrate at 20-25°C in 2 hours and the reaction mass was further stirred for 2 hours. The solid was isolated by filtration, washed with mixture of acetone : water (1 : 1), and dried under vacuum below 45°C to obtain dabigatran etexilate.

Yield: 18.85 g

Efficiency: 75%

Purification:

18 g of Dabigatran etaxilate was stirred in mixture of acetone: ethanol: ethyl acetate (1.5:0.5:6 volumes) at 50-55°C and stirred for 20 minutes. The reaction mass was cooled to 20-25°C and further chilled to 15-20 °C for 3 hours. The solid was isolated by filtration, washed with ethyl acetate and dried under vacuum below 45°C to obtain dabigatran etexilate.

Yield: 13.5 g

Efficiency: 75%

Example 5. Preparation of DAB etexilate mesylate

10 g (0.02 mol) of dabigatran etexilate was dissolved in 200 ml acetone under nitrogen atmosphere. The temperature of the reaction mass was raised to 50-55°C and treated with a solution of 1.86 g (0.0193 mol) of methane sulfonic acid in 50 ml acetone. The reaction mixture was stirred for 45 minutes, then cooled to 20-25 °C and further stirred for 45 minutes. The solid was isolated by filtration, washed with acetone and dried under vacuum below 45°C to obtain dabigatran etexilate mesylate.

Yield: 10 g

Efficiency: 86%

Example 6. Preparation of ethyl 3-(2-((4-carbamimidoylphenylamino)methyl)-l-methyl-N-(pyridin-2-yl)-IH-benzo[d]imidazole-5-carboxamido) propanoate of Formula (ll)using N-acetyl cysteine

10 g (0.020 mol) of ethyl 3-(2-((4-cyanophenylamino)methyl)- l-methyl-N- (pyridin-2-yl)-IH-benzo[d]- imidazole-5-carboxamido) propanoate of Formula (IV) was dissolved in 600 ml EtOH.NH₃ (15-18%w/w) and stirred at 25°C. Added 3.38 g (0.020 mol) of N-acetyl cysteine to the reaction mass and stirred for 24 hours at 70-75°C under 2.0-2.3 kg of pressure. The ethanol was distilled under vacuum and residue was purified by column.

Yield: 5.5 g

Efficiency: 53%

Example 7. Preparation of DAB Amidine of Formula (II) using N-acetyl cysteine

10 g (0.020 mol) of ethyl 3-(2-((4-cyanophenylamino)methyl)- l-methyl-N- (pyridin-2-yl)-IH-benzo[d]- imidazole-5-carboxamido) propanoate of Formula (IV) with 3.5 g (0.021 mol) of N-acetyl-(S)cysteine were initially charged in 10 ml of ethanol. The reaction mixture was heated to 60-65°C, and saturated with ammonia. After 4 hours, ethanol was distilled under vacuum to obtain titled compound as a solid.

Yield: 7.0 g

Efficiency: 67%

Example 8. Preparation of 2-pyridyl impurity B

Part I: 12.0g (0.016 mol) of dabigatran etexilate was added to the solution of 2.8 g (0.07 mol) sodium hydroxide (in 300 ml water and 150 ml ethanol. The reaction mass was stirred for 5 hours. The solution was concentrated under vacuum and neutralized with aq. solution of citric acid (10%v/v). The solid was separated by filtration and washed with cold water and dried under vacuum to afford the acid as a white crystal.

Yield: 8.50 g

Part 11:10 g ( 0.0166 mol) of DAB-Acid obtained in part I was stirred with 25 ml thionyl chloride under nitrogen The temperature of the reaction mass was raised to 40-45°C and maintained for 1 hour. Thionyl chloride was distilled under vacuum completely The residue was stirred in solution of 100 ml toluene and 10 ml triethyl amine at 5-10°C. Added 3.1 g (0.0329 mol) 2-amino pyridine to the reaction mass at 5-10°C under nitrogen atmosphere. Temperature of the reaction mass was raised to 50-55°C and stirred. Toluene was distilled under vacuum and the residue was dissolved in 150 ml DCM. The organic layer was washed with water, dried on sodium sulfate. The organic layer was distilled under vacuum to obtain t crude 2-Pyridyl impurity which was purified by column chromatography.

Yield: 4.0 g

Example 9. Preparation of ethyl 3-(2-((4-cyanophenylamino)methyl)- l-methyl-N- (pyridin-2-yl)-IH-benzo[d]- imidazole-5-carboxamido) propanoate of Formula (IV)

To a solution of N, N-Carbonyldiimidazole (1.17kg, 7.21 mol) and dichloromethane (1 1.25 L), added 2-(4-cyanophenylamino)acetic acid of Formula (VIII), (1.15Kg,6.52 mol) at 30°C under nitrogen atmosphere. The reaction mixture was stirred for 90-100 min and the resulting solid was filtered under nitrogen atmosphere to obtain form Dab glycine CDI complex of Formula (VII).

Dab glycine CDI complex of Formula (VII) was stirred in toluene (9.0L). Added ethyl 3-(3-amino-4-(methyl amino)-N-(pyridin-2-yl)benzamido)propanoate of Formula (VI) (1.5Kg, 4.38 mol) and maintained the reaction at 45-55°C for 3.0 hrs to form DAB coupling intermediate of Formula (V), which further heated to 90-100°C for 3.0 hrs. The reaction mixture was cooled to 25-30°C and the solid precipitated out was isolated by filtration. The wet cake was stirred in water (9.0L), filtered and dried in vacuum below 60 °C to obtain titled compound.

Yield: 1.80kg

Efficiency: 85 %

Example 10. Preparation of ethyl 3-(2-((4-carbamimidoylphenylamino)methyl)-l-methyl-N-(pyridin-2-yl)-IH-benzo[d]imidazole-5-carboxamido) propanoate of Formula (II)

A mixture of ethyl 3-(2-((4-cyanophenylamino)methyl)-l-methyl-N-(pyridin-2-yl)-IH-benzo[d]-imidazole-5-carboxamido) propanoate of Formula (IV) (1.73 kg,3.58mol) was stirred in ethanol denatured with toluene HCI (32-35 % w/w) (20.76 L) at 15- 20°C for 24 hrs. Reaction mass was distilled out completely and the residue was treated with ethanol denatured with toluene. NH₃ (at 10-15% w/w) was added to get the pH 9.0-9.5. The reaction mixture was stirred further for 12.0 hrs. The inorganic was separated by filtration and the filtrate was distilled out and the residue was stirred in ethyl acetate (10 L) . The solid was isolated by filtration and washed with ethyl acetate. The solid was dried in vacuum below 45°C to obtain titled compound.

Yield: 1.70kg

Efficiency: 95 %

Example 11. Preparation of DAB etexilate of Formula (I)

To a solution of ethyl 3-(2-((4-carbamimidoylphenylamino)methyl)-l-methyl-N-(pyridin-2-yl)-IH-benzo[d]imidazole-5-carboxamido) propanoate of Formula (II) (1.61 kg, 3.22mol ), acetone (19.32 L), water( 9.66 L) and potassium carbonate (1.34Kg, 9.69moles ) was added hexyl chloroformate (0.795 kg, 83 moles) slowly at 20-25°C in 2-3 hrs. The reaction mixture was stirred further for 90 min. The solid was filtered and stirred in 7.5 volumes of acetone at 35-40°C. To the clear solution was added dropwise, 7.5 volumes of purified water. The reaction mixture was stirred further for 2 hours at 20-25°C, solid was isolated by filtration and dried at 45°C. The solid was stirred in a mixture of ethanol: ethyl acetate (1 : 10 volume) at 35-40°C to get clear solution, then gradually cooled to 10-15°C and further stirred for 6.0 hours. The solid was isolated by filtration, washed with ethyl acetate and dried under vacuum below 45°C to obtain dabigatran etexilate.

Yield: 1.10 kg

Efficiency: 65%

Example 12. Preparation of DAB etexilate mesylate

Dabigatran etexilate (1.0Kg, 1.59mol) was dissolved in acetone (20.0L) at 50-55°C under nitrogen atmosphere and treated with a solution of methane sulfonic acid (0.15Kg, 1 .56mol) in acetone (1 .5L). The reaction mixture was stirred for 45 minutes, then cooled to 20-25 °C and further stirred for 45 minutes. The solid was isolated by filtration, washed with acetone and dried under vacuum below 45°C to obtain dabigatran etexilate mesylate.

Yield: 1.10kg Efficiency: 95 %

//////////WO-2016027077, WO 2016027077, Cipla Ltd, New patent, Dabigatran

WO 2016025720, New Patent, by Assia Chemicals and Teva on Ibrutinib

WO 2016025720, New Patent, by Assia Chemicals and Teva on Ibrutinib

ASSIA CHEMICAL INDUSTRIES LTD. [IL/IL]; 2 Denmark Street 49517 Petach Tikva (IL)
TEVA PHARMACEUTICALS USA, INC. [US/US]; 1090 Horsham Road P.O. Box 1090 North Wales, PA 19454 (US)

COHEN, Meital; (IL).
COHEN, Yuval; (IL).
MITTELMAN, Ariel; (IL).
MOHA-LERMAN, Elana, Ben; (IL).
TZANANI, Idit; (IL).
LEVENFELD, Leonid; (IL)

The present invention encompasses solid state forms of Ibrutinib, including forms G, J and K, and pharmaceutical compositions thereof.

Ibrutinib, l-{(3R)-3- [4-amino-3-(4-phenoxyphenyl)-lH-pyrazolo [3,4-d] pyrimidin-l-yl] piperidin-l-yl] prop-2-en-l-one, having the following formula,

is a kinase inhibitor indicated for the treatment of patients with B-cell lymphoma.

Ibrutinib is described in US 7,514,444 and in US 8,008,309. Solid state forms, including forms A-F and amorphous form of Ibrutinib, are described in WO 2013/184572.

Polymorphism, the occurrence of different crystalline forms, is a property of some molecules and molecular complexes. A single molecule may give rise to a variety of polymorphs having distinct crystal structures and physical properties like melting point, thermal behaviors (e.g. measured by thermogravimetric analysis - "TGA", or differential scanning calorimetry - "DSC"), X-ray diffraction pattern, infrared absorption fingerprint, and solid state (¹³C-) NMR spectrum. One or more of these techniques may be used to distinguish different polymorphic forms of a compound.

Different salts and solid state forms (including solvated forms) of an active pharmaceutical ingredient may possess different properties. Such variations in the properties of different salts and solid state forms and solvates may provide a basis for improving formulation, for example, by facilitating better processing or handling characteristics, changing the dissolution profile in a favorable direction, or improving stability (polymorph as well as chemical stability) and shelf-life. These variations in the properties of different salts and solid state forms may also offer improvements to the final dosage form, for instance, if they serve to improve bioavailability. Different salts and solid state forms and solvates of an active pharmaceutical ingredient may also give rise to a variety of polymorphs or crystalline forms, which may in turn provide additional opportunities to assess variations in the properties and characteristics of a solid active pharmaceutical ingredient.

Discovering new solid state forms and solvates of a pharmaceutical product may yield materials having desirable processing properties, such as ease of handling, ease of processing, storage stability, and ease of purification, or may serve as desirable intermediate crystal forms that facilitate purification or conversion to other polymorphic forms. New solid state forms of a pharmaceutically useful compound can also provide an opportunity to improve the performance characteristics of a pharmaceutical product. It enlarges the repertoire of materials that a formulation scientist has available for formulation optimization, for example by providing a product with different properties, e.g., a different crystal habit, higher crystallinity or polymorphic stability which may offer better processing or handling characteristics, improved dissolution profile, or improved shelf-life (chemical/physical stability). For at least these reasons, there is a need for additional solid state forms (including solvated forms) of ibrutinib.

Example 1: Preparation of Crystalline Form G of Ibrutinib

[0057] Ibrutinib (0.3 gr, amorphous form) was dissolved in acetic acid (1.2 ml) and the obtained solution was stirred at room temperature overnight followed by the addition of water (2.4 ml). A gum was obtained which was turned into cloudy solution upon stirring. The obtained cloudy solution was stirred for 9 days at room temperature and the obtained precipitate was collected by suction filtration. The obtained solid was dried in an oven at 40°C under vacuum for 16h to obtain form G of Ibrutinib (0.12g), as confirmed by XRPD.

Example 2: Preparation of Crystalline Form J of Ibrutinib

Ibrutinib (5.2 g) was dissolved in Anisole (15 ml), the solution was stirred at room temperature until precipitation was occurred. The slurry was stirred over night at room temperature and the precipitate was collected by suction filtration. The cake was dried in a vacuum oven at 50°C overnight. The obtained product was analyzed by XRPD and found to be form J.

Example 3: Preparation of Crystalline Form J of Ibrutinib

Ibrutinib (10.5 g) was dissolved in Anisole (21 ml) and MTBE (32 ml), the solution was stirred at room temperature until precipitation was occurred . The slurry was heated to reflux and was gradually cooled to room temperature. After 3 hours the precipitate was collected by suction filtration. The obtained product was analyzed by XRPD and found to be form J.

Example 4: Preparation of Crystalline Form G of Ibrutinib

A I L reactor was charged with Ibrutinib (100 g), acetonitrile (417.5 ml_), water (417.5 ml_) and acetic acid (27.15 g). The mixture was heated to 90°C until dissolution; the solution was gradually cooled to 0°C, then heated to 25°C and stirred over 48 hours at 25°C. The obtained slurry was filtered and washed with water (100 ml_). The product was dried overnight in a vacuum oven at 40°C to obtain Ibrutinib form G (72.9 g), as confirmed by XRPD.

Example 5: Preparation of Crystalline Form G of Ibrutinib

A 250 mL round flask was charged with isopropanol (10 ml_) and water (120 ml_), and a solution of Ibrutinib (10 g) in Acetic acid (40 mL) was added dropwise. The mixture was stirred at 25°C for 48 hours. The obtained slurry was filtered and the wet product was slurried in water (50 mL) for 5 min and filtered again. The obtained product was dried under vacuum at room temp in the presence of a N₂ atmosphere and found to be form G, as confirmed by XRPD.

Example 6: Preparation of Crystalline Form K of Ibrutinib

Ibrutinib (10 g) was dissolved in toluene (50 mL) and dimethylformamide (DMA) (30 mL) at room temperature, the solution was heated to 50 °C and water (30 mL) was added. The phases were separated and methyl tert-butyl ether (MTBE) (30 mL) was added to the organic phase. The solution was cooled in an ice bath and seeded with amorphous Ibrutinib. After further stirring at the same temperature the obtained slurry was filtered under vacuum. The obtained solid was analyzed by XRPD and found to be Form K (Figure 5).

//////////////WO 2016025720, WO-2016025720, New Patent,  Assia Chemicals,  Teva,  Ibrutinib 

WO 2016024224, New Patent, Trelagliptin, SUN PHARMA

WO 2016024224, New Patent, Trelagliptin, SUN PHARMA

SUN PHARMACEUTICAL INDUSTRIES LIMITED [IN/IN]; Sun House, Plot No. 201 B/1 Western Express Highway Goregaon (E) Mumbai, Maharashtra 400 063 (IN)

BARMAN, Dhiren, Chandra; (IN).
NATH, Asok; (IN).
PRASAD, Mohan; (IN)

The present invention provides a process for the preparation of 4-fluoro-2- methylbenzonitrile of Formula (II), and its use for the preparation of trelagliptin or its salts. The present invention provides an efficient, simple, and commercially friendly process for the preparation of 4-fluoro-2-methylbenzonitrile, which is used as an intermediate for the preparation of trelagliptin or its salts. The present invention avoids the use of toxic and hazardous reagents, high boiling solvents, and bromo intermediates such as 2-bromo-5-fluorotoluene, which is lachrymatory in nature and thus difficult to handle at a commercial scale.

Trelagliptin is a dipeptidyl peptidase IV (DPP-IV) inhibitor, chemically designated as 2- [[6-[(3i?)-3 -aminopiperidin- 1 -yl] -3 -methyl -2,4-dioxopyrimidin- 1 -yljmethyl] -4-fluorobenzonitrile, represented by Formula I.

Formula I

Trelagliptin is administered as a succinate salt of Formula la, chemically designated as 2-[[6-[(3i?)-3-aminopiperidin-l-yl]-3-methyl-2,4-dioxopyrimidin-l-yl]methyl]-4-fluorobenzonitrile butanedioic acid (1 : 1).

Formula la

U.S. Patent Nos. 7,795,428, 8,288,539, and 8,222,411 provide a process for the preparation of 4-fluoro-2-methylbenzonitrile by reacting 2-bromo-5-fluorotoluene with copper (I) cyanide in N,N-dimethylformamide.

Chinese Patent No. CN 102964196 provides a process for the preparation of 4-fluoro-2-methylbenzonitrile by reacting 4-fluoro-2-methylbenzyl alcohol with cuprous iodide in the presence of 2,2′-bipyridine and 2,2,6,6-tetramethylpiperidine oxide (TEMPO) in an anhydrous ethanol.

Copper (I) cyanide is toxic to humans, and therefore its use in the manufacture of a drug substance is not advisable. In addition, 2-bromo-5-fluorotoluene is converted to 4-fluoro-2-methylbenzonitrile by refluxing in N,N-dimethylformamide at 152°C to 155°C for 24 hours. This leads to some charring, resulting in a tedious work-up process and low yield. Furthermore, the use of reagents like cuprous iodide, 2,2′-bipyridine, and 2,2,6,6-tetramethylpiperidine oxide (TEMPO) is hazardous and/or environmentally-unfriendly, and therefore their use in the manufacture of a drug substance is not desirable.

The present invention provides an efficient, simple, and commercially friendly process for the preparation of 4-fluoro-2-methylbenzonitrile, which is used as an intermediate for the preparation of trelagliptin or its salts. The present invention avoids the use of toxic and hazardous reagents, high boiling solvents, and bromo intermediates such as 2-bromo-5-fluorotoluene, which is lachrymatory in nature and thus difficult to handle at a commercial scale.

EXAMPLES

Example 1 : Preparation of 4-fluoro-2-methylbenzaldoxime

4-Fluoro-2-methylbenzaldehyde (1.38 g) was added to ethanol (10 mL) to obtain a solution. To this solution, hydroxylamine hydrochloride (2.76 g) and pyridine (1 mL) were added, and then the mixture was stirred at 20°C to 25 °C for 3 hours. The solvent was recovered up to maximum extent from the reaction mixture under reduced pressure to afford the title compound. Yield: 3.1 g

Example 2: Preparation of 4-fluoro-2-methylbenzaldoxime

4-Fluoro-2-methylbenzaldehyde (5 g) was added to ethanol (37 mL) to obtain a solution. To this solution, hydroxylamine hydrochloride (10 g) and N,N-diisopropylethylamine (3.6 mL) were added, and then the mixture was stirred at 20°C to 25 °C for 2 hours. The solvent was recovered up to maximum extent from the reaction mixture under reduced pressure to afford the title compound. Yield: 3.1 g

Example 3 : Preparation of 4-fluoro-2-methylbenzaldoxime

4-Fluoro-2-methylbenzaldehyde (10 g) was added to ethanol (40 mL) to obtain a solution. To this solution, hydroxylamine hydrochloride (20 g) and N,N-diisopropylethylamine (7.5 mL) were added, and then the mixture was stirred at 20°C to 25 °C for 4 hours. The solvent was recovered from the reaction mixture under reduced pressure to afford the title compound. Yield: 11.0 g

Example 4: Preparation of 4-fluoro-2-methylbenzaldoxime

4-Fluoro-2-methylbenzaldehyde (50 g) was added to ethanol (500 mL) to obtain a solution. To this solution, hydroxylamine hydrochloride (70 g) and N,N-diisopropylethylamine (36 mL) were added, and then the mixture was stirred at 20°C to 25 °C for 6 hours. The solvent was recovered from the reaction mixture under reduced pressure to afford the title compound. Yield: 51.0 g

Example 5 : Preparation of 4-fluoro-2-methylbenzaldoxime

4-Fluoro-2-methylbenzaldehyde (20 g) was added to ethanol (200 mL) to obtain a solution. To this solution, hydroxylamine hydrochloride (20 g) and N,N-diisopropylethylamine (18 mL) were added, and then the mixture was stirred at 20°C to 25 °C for 4 hours. The solvent was recovered from the reaction mixture under reduced pressure to obtain a residue. Deionized water (60 mL) was charged into the residue, and then the slurry was stirred at 0°C to 5°C for 1 hour. The solid obtained was filtered, then washed with deionized water (2 x 20 mL). The wet solid was dried in an air oven at 40°C to 45 °C for 4 hours to 5 hours. The crude product obtained was recrystallized in ethanol (50 mL) to afford the pure title compound. Yield: 21.0 g

Example 6: Preparation of 4-fluoro-2-methylbenzaldoxime

4-Fluoro-2-methyl benzaldehyde (50 g) was added to ethanol (500 mL) to obtain a solution. To this solution, hydroxylamine hydrochloride (50 g) and N,N-diisopropylethylamine (46.4 mL) were added, and then the mixture was stirred at 20°C to 25 °C for 4 hours. The solvent was recovered from the reaction mixture under reduced pressure to obtain a residue. Deionized water (150 mL) was charged to the residue, and then the slurry was stirred at 0°C to 5°C for 1 hour. The solid obtained was filtered, then washed with deionized water (2 x 50 mL). The wet solid was dried in an air oven at 40°C to 45 °C for 4 hours to 5 hours. The crude product obtained was recrystallized in ethanol (200 mL) to afford the pure title compound. Yield: 53.5 g

Example 7: Preparation of 4-fluoro-2-methylbenzonitrile

4-Fluoro-2-methylbenzaldoxime (3.1 g) and phosphorous pentoxide (1 g) were added to toluene (30 mL) to obtain a reaction mixture. The reaction mixture was refluxed at 110°C to 115°C for 24 hours. After completion of the reaction (monitored by TLC), the reaction mixture was cooled to 25°C to 30°C. Deionized water (30 mL) was added to the mixture and then the layers were separated. The organic layer was concentrated under reduced pressure to afford the title compound. Yield: 1.1 g

Example 8: Preparation of 4-fluoro-2-methylbenzonitrile

4-Fluoro-2-methylbenzaldoxime (3 g) and phosphorous pentoxide (2 g) were added to toluene (30 mL) to obtain a reaction mixture. The reaction mixture was refluxed at 110°C to 115°C for 24 hours. After completion of the reaction (monitored by TLC), the reaction mixture was cooled to 25°C to 30°C. Deionized water (30 mL) was added to the mixture and then the layers were separated. The organic layer was concentrated under reduced pressure to afford the title compound. Yield: 1.0 g

Example 9: Preparation of 4-fluoro-2-methylbenzonitrile

4-Fluoro-2-methylbenzaldoxime (5 g) and concentrated sulphuric acid (2 mL) were added to toluene (100 mL) to obtain a reaction mixture. The reaction mixture was refluxed at 110°C to 115°C for 5 hours. After completion of the reaction (monitored by TLC), the reaction mixture was cooled to 25°C to 30°C. Deionized water (50 mL) was added to the mixture and then the layers were separated. The organic layer was concentrated under reduced pressure to afford the title compound. Yield: 3.24 g

Example 10: Preparation of 4-fluoro-2-methylbenzonitrile

4-Fluoro-2-methylbenzaldoxime (25 g) and concentrated sulphuric acid (35 g) were added to toluene (500 mL) to obtain a reaction mixture. The reaction mixture was refluxed at 110°C to 115°C for 6 hours. After completion of the reaction (monitored by TLC), the reaction mixture was cooled to 25°C to 30°C. Deionized water (250 mL) was added to the mixture and then the layers were separated. The organic layer was concentrated under reduced pressure to afford the title compound. Yield: 20.5 g

Example 11 : Preparation of 4-fluoro-2-methylbenzonitrile

4-Fluoro-2-methyl benzaldoxime (5 g) and sodium bisulphate monohydrate (3.1 g) were added to toluene (50 mL) to obtain a reaction mixture. The reaction mixture was refluxed at 110°C to 115°C for 12 hours. After completion of the reaction (monitored by TLC), the reaction mixture was cooled to 25°C to 30°C, then filtered, and then washed with toluene (10 mL). The filtrate was concentrated under reduced pressure to afford the title compound. Yield: 3.0 g

Example 12: Preparation of 4-fluoro-2-methylbenzonitrile

4-Fluoro-2-methyl benzaldoxime (50 g) and sodium bisulphate monohydrate (31.6 g) were added to toluene (500 mL) to obtain a reaction mixture. The reaction mixture was refluxed at 110°C to 115°C using a Dean-Stark apparatus for 12 hours. After completion of the reaction (monitored by TLC), the reaction mixture was cooled to 25 °C to 30°C, then filtered, and then washed with toluene (100 mL). The filtrate was concentrated under reduced pressure to afford a crude product. The crude product obtained was recrystallized in a mixture of toluene (200 mL) and hexane (500 mL) to afford the title compound.

Yield: 38.0 g

Sun Pharma managing director Dilip Shanghvi.

/////////////WO 2016024224, New Patent, Trelagliptin, SUN PHARMA